What grade is your son in? Might this be a 'one door closes and another one opens' situation? Were his needs being met in the current gifted program? Can he take 'AP track' classes without being in the gifted program? Would he be happier homeschooling with classes at the local Community College or University anyway? Was he happy in the first place?
Can you back up and give us the bigger picture? Don't be afraid of writing too much (as long as it doesn't give away you identity) - even if we don't help much, I find that the act of writing for a group that really cares can be very helpful.
Love and More Love,
grinity